Sewing machine



May 28 :1

Filed March 21, 1955 M. FRANCOIS SEWING MACHINE 2 sheeis 1 Marcel $29,

' FRANCOIS SEWING MAC 2 Sheets-Sh 2 Filed March 21, 1955 SEWING MACHINE Marcel Frangois, Chatenay-Malabry, France, assignor to Societe de lUsine de la Marque, Paris, France, a French body corporate it c Application March 21, 1955, Serial No. 495,446

Claims priority, application France March 24, 1954 3 Claims. (Cl. 112-220) The present invention relates to sewing machines of the type in which the various mechanisms are carried by a vertical thin rigid U-shaped plate which has horizontal branches and is connected to or is integral with a stand.

An object to the invention is to provide a sewing machine which is extremely simple in construction, very easily set and whose elements are easily accessible not only for assembling and disassembling and possible repairs but also and above all for adjustment starting with the needle bar relative to the movements of which all the other movements may be co-ordinated.

A further object of the invention is to provide a sewing machine in which the various mechanisms cooperating in the formation of the stitches, the feeding of the Work and the supply of the thread are disposed on the same side of the plate, the driving shafts of these mechanisms extending through this plate and being rigid with driving devices situated on the other side of the plate.

According to another feature of the invention the various driving devices comprise rotatable members fixed on the driving shaft of the various mechanisms co-operating in the formation of the stitches, one of these rotatable members being a driving member and being connected to the other members by a single endless flexible transmission member which comprises preferably a chain or belt which includes driving bars and is operative on both sides thereof.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings given merely by way of example and in which:

Fig. 1 is a perspective view of a machine embodying the invention seen from the side of the plate carrying the driving devices, and

Fig. 2 is a similar view of the other side of the machine, this figure being completed by a part of the two shells forming the housing which surrounds the plate for protecting the various mechanisms without actually supporting the latter.

According to the illustrated embodiment, the machine comprises a stand 1 to which is attached, by means of feet 2 and screws 3, a vertical plate 4 which is relatively thin, rigid, preferably reinforced by ribs 5 and is of steel or other strong material. This plate is notched at 6 so as to form a kind of U-shaped member whose two branches are substantially horizontal, the upper branch forming a cantilever support. Disposed on this plate are the various mechanisms for forming the stitches and supplying the thread, and the driving devices for these mechanisms.

According to the invention all said mechanisms are situated on the same side (see in Fig. 2), whereas all the driving devices are disposed on the other side of the plate (see Fig. 1).

The mechanisms for forming the stitches are conventional and those shown in Fig. 2 are only given by way of example.

The lower branch of the plate 4 carries at its end Patent 2,793,600 fatented May 28, 1957 the usual rotary hook for forming the stitches which is generally indicated by the reference numeral 7. This hook is driven by a shaft 8 which extends through the plate in a direction perpendicular to the latter.

Disposed to one side of and above this lower branch of the plate, is a mechanism for shifting the work. This mechanism is seen in Fig. 1 and comprises claws 9 which are carried by a rigid blade or strip 10 which is engaged at its rear end in a fork 11- formed in a journal 11 carried by the plate. This claw-carrying blade is capable of pivoting in the vertical direction about the axis of the journal 11 and in the horizontal direction about a vertical axis 11 carried by the fork 11 The claws 9 and the claw-carrying blade are moved backwards and forwards by a cam member 12 comprising a groove 13 which is inclined at a suitable angle and in which engages a roller 13 (Fig. 1) carried by the claw-carrying blade.

The member 12 is guided in the direction parallel to the lower branch of the plate 4 by a rod slidable in a bracket 15 fixed to the lower branch of the plate. Movements are imparted to the member 12 by a connecting rod 16 which is mounted for pivotable movements about a pin 17 and whose rear part forms a .fork 18 which co-operates with a substantially triangular cam 19. The latter is angularly adjustable owing to the provision of screws 20 which connect it to a pulley 21 keyed to a shaft 22 extending through the plate 4. The shaft 22 is connected to an electric motor 26 by transmission means comprising the pulley 21 is connected by a belt 23 which connects the latter to a driving pulley 24 keyed to the shaft 25 of an electric motor 26. The shaft 22 is therefore the driving shaft of the mechanism.

The claws 9 are moved up and down by an eccentric (not seen in Fig. 2) which is keyed to the shaft 22. This eccentric, which is keyed in suitable angular position relative to the cam 19, is adapted to pivot a fork 26 about a pin 27. The latter is carried by a bell crank 28 which is pivotable about a pin 29 secured to the plate 4. An operating knob 30 permits regulating the angular position of the bell crank 28 and therefore that of the pin 27 and in consequence that of the end of the lever 26. This end carries a roller 31 against which the claw-carrying blade 10 is urged by the action of a spring (not shown).

The oscillations of the fork 26 therefore result in the up and down movement of the claws. The lever 28 with its operating knob 30 permits, if required, moving the pin 29 sufficiently downwardly so that for certain sewing the claws may be completely withdrawn relative to the work.

The upper branch of the plate 4 carries the vertical needle bar 32 which is connected by a rod. 33 to a crank 34 keyed to a shaft 35. The crank 34 imparts to the needle bar 32 vertical up and down movements in a support 36.

A thread take-up is shown at 38 in Fig. 2, this thread take-up being keyed to a shaft 39 which also extends through the plate 4, in which it is journalled.

Referring now to Fig. l, which shows the driving devices for the above-mentioned mechanisms. Keyed to the shaft 22, which it will be recalled is connected by the pulleys 21 and 42 and the belt 23 to the shaft of the electric motor 26, is a gear wheel or sprocket 40. The latter, which constitutes a driving wheel, is adapted to drive the chain-belt 41 provided with driving bars on both sides. This chain moves with respect to itself in the direction of arrow f and passes round a first sprocket 42 fixed to the shaft 8. The latter is in fact constituted by a screw having shoulders which permits locking the hook 7 in the desired angular position relative to the movements of the needle bar. After the sprocket 42,

the chain passes round a return sprocket or pulley 43 which also forms a tension sprocket, the spindle 44 thereof being movable in an elongated slot 45 in the plate 1 and being held in the adjusted position by means of nuts 46. The chain thereafter passes round a sprocket or gear wheel 47 which is angularly adjustable, for example by means of screws 48, on a shaft 49. It then extends along the upper edge of the plate and passes round another sprocket 50 also fixed in adjustable angular position, by means of screws 51, on the shaft 35 adapted to impart to the needle bar 32 its vertical movements in the support 36.

It will be noticed that this .sprocket 50 drives the shaft 39 of the thread take-up 38 by means of a crank pin 52 and a rod 53 which is slidable in this crank pin and in a sleeve 54 fixed in adjustable angular position by a screw 55 on the shaft'39 of the thread take-up.

Lastly, the chain passes round a return sprocket 56 and attains the driving sprocket 40.

It will be observed that the mechanisms and driving devices are enclosed in a housing comprising for example two half-shells 57 and 58 which are partially shown in Fig. 2. These half-shells are fixed together and to the plate if need be by elastic connections. They may also be fixed to the stand.

As can be seen, the side of the plate carrying the mechanisms contributing to the formation of the stitches and the supply of the thread, is entirely free from any driving device likely to encumber this face. The latter being fully available for the arrangement of the various mechanisms which are, furthermore, readily accessible.

after having removed the half-shell 58.

The construction is extremely simple and, owing to the position of the adjusting devices, it is possible to adjust each'movement separately relative to the up and down movement of the needle bar 32 without having to remove the chain or belt 41.

The adjustable position of the tension sprocket 43 ensures suitable adjustment of the tension of the chain 41 and avoids the necessity of exact dimensions between the various shafts and of an exact chain length.

Although a specific embodiment of the invention has been described hereinbefore, many changes and modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims.

Thus the plate instead of being of one piece as illus trated may comprise several elements suitably assembled (for example comprise a lower branch, an upright and an upper branch). The claw-carrying blade 10 may be engaged in a pin 11 rigidly fixed to the plate the vertical movements of the claws being then permitted by elastic flexion of this blade. The motor may be coupled directly to a shaft driving the chain 41. The chain may be replaced by a link, roller or dummy roller chain similar to those used on bicycles. The tension of the chain or of the belt may be ensured automatically by mounting the tension sprocket or pulley on a shaft which moves automatically under the action of counterweights so as to provide a constant suitable tension of the belt, notwithstanding the variations in tension which tend to occur owing to atmospheric conditions, heat, etc.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a sewing machine: a stand; a thin rigid vertical U-shaped plate having horizontal branches, the lower branch of the plate being fixed to the stand; at least four shafts some of which extend through the lower branch whereas the others extend through the upper branch of said plate, the shafts protruding from both sides of the latter; a stitch-forming mechanism keyed on one of said shafts and a work-feeding mechanism operatively connected to another of said shafts both of said mechanisms being disposed on one side of the lower branch of the plate; a thread-supplying mechanism disposed on the side of the upper branch corresponding to the side of the lower branch on which said stitch-forming and work-feeding mechanisms are disposed, said threadsupplying mechanism comprising a needle bar and a thread take-up operatively connected to a third shaft selected from said shafts; rotatable members disposed on the opposite side of the two branches to said mechanisms keyed on the corresponding ends of said shafts; a flexible endless member interconnecting said rotatable members; an electric motor and transmission means between said motor and one of said shafts for driving said mechanisms, through the medium of said flexible member, said rotatable members and said shafts.

2. Sewing machine as claimed in claim 1, wherein a crank pin is keyed on said third shaft and a connecting rod connects said crank pin to said needle bar.

3. Sewing machine as claimed in claim 2, wherein said thread take-up is keyed on a fourth shaft of said shafts, and a link and crank connection, disposed on the same side of the upper branch as the rotatable members, connects said fourth shaft to said third shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,325,928 Zeier Aug. 3, 1943 2,633,092 Robert et al Mar. 31, 1953 FOREIGN PATENTS 676,073 Great Britain July 23, '1952 

